JPS63299722A - Voltage regulation relay - Google Patents

Abstract

PURPOSE:To stably supply the voltage of a power system by comparing an average value of all the average values of voltages, each at each of a plurality of ground points of the system with a set voltage, and controlling the tap switching of an on-load tap changing transformer by the compared result. CONSTITUTION:The end voltages of the loads 3a, 3b in a power system are input to an input converter 12, and digitally converted voltages are input to a voltage regulating relay 13. The relay 13 calculates a time average voltage within a predetermined time for each input load terminal voltage, and then calculates an average value (whole average voltage) of all the time average voltages. The obtained whole average voltage is compared with a preset voltage, and if the whole average voltage is larger than the set voltage, a down command for executing the tap change for reducing the voltage with respect to an on-load tap changing transformer 9 is output, while if the while average voltage is lower than the set voltage, a rise command signal is output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voltage regulating relay used for regulating the voltage of a power system to a constant level.

[Conventional technology]

The power system is provided with a load tap switching voltage regulator, and by appropriately switching the tag, the load end voltage of the power system is maintained constant. The tag switching of this on-load tap-changing transformer is performed by a voltage regulating relay.

FIG. 4 is a system diagram of a conventional line voltage regulator. In the figure, 1 is a power transmission line, 2 is a power source that supplies power to power transmission line 1, and 3
A and 3b are loads connected to the power transmission line 1, 4 is a current transformer that detects the current flowing to the power transmission line 1, and 5 is an auxiliary transformer.

V・ is the power supply voltage of the power supply 2-, Ishi is the load current of the transmission line 1, L,,L, is the transmission [f! 10 track reactance,
R1! is the line resistance of power transmission line 1, Z1□ZL is the load impedance of loads 3a and 3b, respectively, and v is load 3a
Indicates the terminal voltage of

6 is a Kucho transformer resistor connected to the auxiliary transformer 5, and 7 is a line voltage drop compensator. This line voltage drop compensator 7 is composed of a variable reactance 7L and a variable resistor 7R. 8 is voltage a14! It is an iE relay. va is the voltage of variable resistor 6, L! is the reactance of the variable reactance 7L, Rs is the resistance of the variable resistor 7L, vb is the output voltage of the line voltage drop compensator 7, vc is the input voltage of the voltage adjustment relay 8, and iL is the detection % of the current transformer 4. Show flow.

The reactance L and the resistance Rs set in the line voltage drop compensator 7 are connected to the transmission line 1 and the power of the next load is #&
A value proportional to the line reactance and line resistance between the center of the demand distribution and the power supply 2 is selected.

Now, if the center of the load distribution is the load aaK and this voltage V is to be controlled, the voltage vt is proportional to the following formula % formula % If the ratio value Vc is given to the voltage adjustment relay 8. , the voltage 14 regulator 8 can control the tap switching of the on-load tap-changing transformer based on this, thereby making it possible to maintain the voltage v1 at the target voltage. Since the variable resistor 6 and the line voltage drop compensator 7 are provided, the voltage VC can be determined as follows.

VC= V@ Vb=Vs −(J” Ls +
Rm ) lc That is, by setting impedances Ls and Rs in the line voltage drop compensator 7 in a simulated manner, it is possible to obtain a specific voltage drop proportional to the line impedance, thereby obtaining a voltage VC proportional to the voltage V. can.

[Problem that the invention seeks to solve]

In the above-mentioned line voltage regulator, reactance Ls,
Resistor 1 is set based on predictions of power demand.

However, the power demand within the power system is not always constant and usually changes. Therefore, the center of demand distribution also changes accordingly. As a result, the actance L1. The resistance R, no longer matches the actual situation, and thereby the value of the voltage vc also fluctuates, and the voltage regulating relay 8 is no longer able to perform an appropriate voltage vI4. This is shown in wJs diagrams (a) to (
This is explained by d).

FIG. 5(a) is a load distribution diagram of the power system. 1 is a power transmission line, 2 is a power source, 3. ~3n represents the load, Z and 1 to Z cone represent the line impedance. Ninth, for ease of understanding, it is assumed that the power demand of each load 31 to 3fi is equal. Therefore, the voltage V to be controlled is at the midpoint of the line, and the impedance L, , R, of the line voltage drop compensator 7 is also set according to the M% impedance from the power supply 2 to this midpoint.

Figures 5(b) to 5(d) are line voltage distribution diagrams, and the fifth
Figure (b) is a voltage distribution diagram when there is no change in the power demand of the load. In this case, the voltage vL and the voltage adjustment relay 80 input voltage Vc match. However, when a change occurs in the power demand of the load, a mismatch occurs between the two voltages.

FIG. 5(c) is a voltage distribution diagram in the following case where power demand is concentrated on the load on the W source side. In this case, the center of the power demand distribution is on the power source side, but the line impedance up to that point is small because the distance from the power source 2 is short. However, since the impedance L,, 几, set in the line voltage drop compensator 7 is fixed, even though the actual line voltage shows the distribution shown by the broken line, the line voltage drop compensator 7 actually It is assumed that there is a line voltage distribution shown by the solid line that is lower than the line voltage distribution of . Consequently, voltage VC will be lower than voltage vL, and controlling the on-load tap-changing transformer based on this lower voltage VC will result in overcompensation.

FIG. 5(d) is a voltage distribution diagram in the case where, conversely, the electric power is concentrated on the load on the side far from the power source. In this case, Figure 5 (
In contrast to the case shown in c), the line voltage drop compensator 7 assumes that there is a line voltage distribution shown by the solid line that is higher than the actual one-way voltage distribution shown by the broken line, resulting in insufficient compensation.

As described above, conventional devices have problems in that they cannot respond to changes in the power demand of the load and cannot stably control the voltage of the power system.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above and to provide a voltage regulating relay that can stably control the voltage of a power system even if the power demand of the load changes.

[Ninth way to solve the problem]

Ninth to achieve the above object, the present invention provides a voltage regulating relay that controls tag switching of on-load tap-changing transformers to keep the voltage of the power system constant, by inputting voltages at multiple points in the power system. input means and the entered %
A first calculation means for calculating the time average voltage for each voltage, a second calculation means for calculating the total average voltage of each of these time average voltages, and a comparison means for comparing the total average voltage with a set voltage. , and an output means for outputting a switching control signal to the on-load tag switching transformer in accordance with the comparison result.

[For production]

The voltages at each load end in the power system are output in a hurry, and these voltages are input to the Asahi Doke-kakei gage. In the voltage a11 scale,
Enter f? :,/? ! rLoad end load end voltage The time average voltage within a fixed time is calculated, and then the average 1m (total average voltage) of all these time average voltages is calculated. Then, the obtained total average voltage is compared with a preset set voltage, and if the total average voltage is higher than the set voltage, a drop command is issued to execute tag switching to drop the voltage to the tag switching transformer during load. A signal is output, and if the total average voltage is lower than the set voltage, an increase command signal is output.

〔Example〕

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a system diagram of a voltage regulating electric appliance according to an embodiment of the present invention. In the figure, 1 is a power transmission line, and 3a and 3b are loads.

Reference numeral 9 indicates a load tap changer, and reference numeral 10 indicates a circuit breaker, both of which are provided on the power transmission line 1. 11 is an auxiliary transformer that detects the load end voltage of each load. A secondary input f converter is provided at each load end, and an auxiliary transformer 12a and an auxiliary transformer 1 are provided at each load end to reduce the voltage at the load end proportionally to an appropriate value.
2. RMS value converter 12 b that converts the output of a into an effective value.
, an A/D converter 12C1 and an A/D converter 12C that convert the output of the effective gLK converter 12b into a digital value.
It is comprised of a digital output section 12d that converts the signal and outputs a ratio value.

Reference numeral 13 denotes a voltage adjustment device, and a calculation unit 13 performs necessary calculations and control of the digital signal input/output section 13a1.
b, a storage section 13C1 consisting of a ROM (read only memory) and a RAM (random access memory), and an input/output section 13d that is a digital output section.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG. 2 and the calculation explanatory diagrams shown in FIGS. 3(a) to 3(c). From the power transmission edge 1 to each load 3a, 3b,...
Power is supplied to...

At this time, each load end voltage is input to the input converter 12 via the auxiliary transformer 11.12a. The input specific voltage is converted into an effective value by an effective value converter 12b. As a result, even if a large distortion occurs in the AC input voltage, only the effective value component can be extracted accurately. The signal converted into an effective value is converted into a digital value by A/υ' converter 12C. Note that the timing of the conversion of this A/D converter 12c is the voltage,)
It is controlled by a timing signal output from b. The converted nine voltage values are outputted from the output section 12d and are sequentially input to the voltage regulating relay 13 via its input/output section 13a for each load end voltage (step S shown in FIG. 2).

The voltages taken into the voltage regulating relay 13 are sequentially stored in the storage unit 13c for a certain period of time, and after a certain period of time, these voltages are taken out, and the average value within the certain period of time is calculated for each load end voltage. (Step S).

The calculation of this average value will be explained with reference to FIG. 3(a).

FIG. 3(a) is a waveform diagram of the load terminal voltage V(t) of the load. The load end voltage at time T is V (To),
Time (T0+ To) Niohru load m voltage + s V
(T, +Tn). Here, the voltage is averaged over the certain period of time, and is calculated by the following equation.

This calculation is executed by the calculation unit) 13b.

FIG. 3(b) is a diagram showing the arrangement of each load on the power transmission grid, where 1 indicates the transmission xi, 2 indicates the power supply, and P and ˜P indicate the positions of the respective loads.

FIG. 3(c) is a diagram showing the average voltage of each load during time Tn, and the average voltage of the load end voltage at position P is V, (
t), and the average voltage of the load end voltage at position [P, is V
It is denoted by n(t).

Next, the overall average voltage of the average voltages of these load end voltages is calculated by the calculation unit 13b (step Ss)
. Using the expression shown in FIG. 3(c), the overall average voltage V can be obtained from the following formula.

The above average voltage V is the voltage that should originally be controlled.

The average storm pressure V obtained in this manner is compared with a predetermined set voltage (step 84), and if the average voltage V is higher than the set voltage, the on-load tap changer transformer 9 is A descending command to change the tap in the direction of lowering the voltage is output (hand II Ss).

Then, based on the signal from the on-load tag switching transformer 9, it is determined whether or not the voltage switching has been completed in response to this step-down command (step S), and the output of the step-down command is continued until the voltage switching is completed. do.

If it is determined in step S4 that the average voltage V is not higher than the set voltage, then it is determined whether the average voltage V is lower than the set voltage (step S, ). In this process, if it is determined that the average voltage V is not lower than the set voltage, the process ends because the average voltage V and the set voltage are equal. If it is determined in step S that the average voltage V is lower than the set voltage, a step-up command is output to the on-load tag switching transformer 9 to switch the tap in the direction of increasing the voltage. ). and,
Based on the signal from the on-load tap change transformer 9, it is determined whether the voltage switching has been completed in response to this increase command.In step S,), the output of the increase command is continued until the voltage switching is completed. Once all steps have been completed, preparations are made for the next data processing. Then, the processing from +l11iLs is repeated again.

In this way, in this embodiment, the average voltage at the load terminal is constantly checked at all times, and the average voltage of all the average voltages at each negative terminal is compared with the set voltage. Even if significant fluctuations occur, the voltage of the power system can be appropriately controlled.

〔Effect of the invention〕

As described above, in the present invention, the average voltage at each point of the voltage at multiple points in the power system is calculated, the average voltage of all these average voltages is determined and compared with the set voltage, and the result of this comparison is Since the tap switching of the seismic pressure device is controlled during load tap switching, the voltage of the power system can be stably supplied even if the load fluctuates.

[Brief explanation of the drawing]

1st I2! A is a system diagram of a voltage regulating relay according to an embodiment of the present invention, FIG. 2 is a flowchart explaining the operation of the voltage regulating relay shown in FIG. 1, and FIGS. 3(a), (b), (C
) is an explanatory diagram illustrating the calculations executed by the voltage-cotton adjustment device shown in Figure 1, Figure 4 is a system diagram of a conventional line voltage regulator, and Figures 5 (a), (b), (C ) and (d) are a load distribution diagram and a line voltage distribution diagram. 1...Transmission line, 3a, 3b...Load,
9...Tap switching transformer on load, 12...
・-Manual power converter, 13...Bending voltage adjustment relay No. 2 Figure 3 Position → No. 5 Layer - Coarse layer → Layer -

Claims (1)

[Claims] 1. In a voltage regulating relay that adjusts the voltage of a power system to a constant level by controlling tap switching of a tap-changing transformer at the time of load, an input means for inputting voltages at a plurality of points in the power system, and each input voltage A first calculation means for calculating the time average voltage for each time, a second calculation means for calculating the total average voltage of each time average voltage calculated by the first calculation means, and a second calculation means for calculating the total average voltage of each time average voltage calculated by the first calculation means. Comparing means for comparing the calculated total average voltage with a predetermined set voltage, and output means for outputting a switching control signal to the on-load tap switching transformer according to the comparison result of the comparing means. A voltage regulating relay characterized by: